An Orthogonal Frequency Division Multiplexing (OFDM) method, such as Long Term Evolution (LTE), standardized by 3rd Generation Partnership Project (3GPP) attracts attention as a communication method for the next generation. In a communication method such as LTE, a receiver needs to conduct determination on synchronization on the basis of reception quality of a control channel, and to report a state of synchronization to a higher-level layer, as stipulated in NPL 1 and NPL 2. Then, the higher-level layer makes a judgment on a start and an end of a process of transmission to a base station, according to information such as a result of determination on synchronization by the receiver, and so on.
In a conventional Wideband-Code Division Multiple Access (W-CDMA) communication method, the determination on synchronization is conducted by way of comparing a Signal-to-Interference Ratio (SIR) value measured by the receiver, with criterion values called Qin and Qout.
In the meantime, adding a moving average process is proposed in PTL 1. Thus, the process makes it possible to stably conduct determination on synchronization and transmission control even when a measured SIR value includes a variation.
Meanwhile, in the OFDM communication method, used is Exponential Effective SNR Mapping (EESM), as described in NPL 3. Using EESM makes it possible to calculate an SNR representing a reception quality (hereinafter called “reception quality SNR”) in a reflection of a Block Error Ratio (BLER) of a control channel, being independent of channel propagation conditions.